1. Field of the Invention
The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus, such as a video camera equipped with a camera shake correction function.
2. Description of the Related Art
In the case where an image pickup apparatus equipped with the camera shake correction function is mounted on a tripod for shooting, a shake detection signal from a shake-detecting means becomes smaller. Conventionally, in view of this, there has been proposed a technique of changing the amplification factor and resolution of the shake detection signal when it is detected that an image pickup apparatus is mounted on a tripod, to thereby make it possible to correct even a minute shake with accuracy (see Japanese Laid-Open Patent Publication (Kokai) No. 2000-284337).
Further, in order to obtain a sufficient shake correction effect, there has been proposed a technique of changing the correction frequency band of the shake detection signal when it is detected that the image pickup apparatus is mounted on a tripod (see Japanese Laid-Open Patent Publication (Kokai) No. H02-173625).
However, although the above-mentioned conventional techniques propose accurate shake correction which is to be performed, when it is detected that the body of the image pickup apparatus is mounted on a tripod, by increasing the amplification factor of the shake detection signal, or expanding the correction frequency band to a lower frequency so as to change the characteristics of shake correction control.
Recently, a recorder provided in an image pickup apparatus has come to use a recording medium, such as a DVD (Digital Versatile Disk) or a hard disk. This type of recorder generates larger driving vibration during recording than a conventionally used tape-based recorder. For this reason, when shooting is performed with the image pickup apparatus body fixedly mounted on the tripod, the apparatus body can be vibrated by the driving vibration of the recorder incorporated therein.
For example, when the rotational vibration frequency of a DVD drive for double-speed writing is about 28 to 46 Hz, the driving vibration of the DVD drive and a frequency band (1 to 20 Hz) for shake correction are close to each other.
In the apparatus body, the driving vibration propagates through a lens unit, a mechanism of the recorder, a gyro sensor, and so forth at respective different frequencies and amplitudes, so that when the above-mentioned conventional methods are applied, the gyro sensor can erroneously detect rotational vibration caused during recording operation of the DVD drive, as a camera shake.
As a consequence, in spite of the body of the image pickup apparatus being actually at rest, an optical or electronic shake-correcting means carries out a shake correcting operation, which causes fluctuation or oscillation of an output image. As described above, the conventional image pickup apparatuses are not capable of performing proper shake correction, and suffers from low accuracy of shake correction.